In FHIR-28182, we had indicated that we couldn't rename the 'old' and 'new' coverages to 'coverageToMatch' and 'coverageToLink' because of pending regulation.  We were similarly unable to drop the requirement to echo back the coverageToLink or to simplify the response to simply return the member identifier rather than a fully populated Patient instance.

Now that we're not under a pending regulation deadline, it seems appropriate to fix all of these issues so that the $member-match operation is both clearer and simpler.